1. Field of the Invention
The present invention relates to a method of scanning a substrate, and a method and an apparatus for analyzing crystal characteristics. More particularly, the present invention relates to a method of scanning a substrate using an electron beam, and a method and an apparatus for analyzing crystal characteristics.
2. Description of the Related Art
Generally, semiconductor devices are manufactured by repeatedly performing a deposition process, a chemical and mechanical polishing (CMP) process, a photolithography process, an etching process, an implanting process, a cleaning process, an inspecting process, and so on. Due to design rule reductions of the semiconductor devices, circuit patterns of the semiconductor devices have also been reduced to a size similar to that of a typical crystal of a material included in the circuit patterns. Characteristics of the material, such as physical characteristics, electric characteristics, surface characteristics, and internal characteristics, are influenced by crystal characteristics having a nano-scale in a range of a few nanometers to several tens of nanometers. In addition, the above-described crystal characteristics need to be adjusted while manufacturing the semiconductor devices.
An electron beam has been widely used for analyzing crystal characteristics. A conventional method of analyzing crystal characteristics may begin with irradiating an electron beam onto an analysis region of a substrate. This will instantly charge the analysis region of the substrate with electrons. Some electrons are then elastically collided with atomic nuclei in the analysis region and discharged and scattered out from a surface of the analysis region of the substrate.
Hereinafter, a scattered electron resulting from this elastic collision between irradiating electrons and target atomic nuclei is referred to as a back-scattered electron.
Back-scattered electrons are detected by an analysis device. A diffraction pattern, for example a diffraction spectrum, is obtained on a basis of the detected back-scattered electrons. The crystal characteristics are analyzed by using the diffraction pattern. U.S. Pat. No. 5,466,934 (issued to Brent, et al.) discloses just such a conventional method and an apparatus for detecting crystal defects by using back-scattered electrons.
Although an analysis device using the diffraction pattern has a resolution degree inferior to that of a transmission electron microscope, the above analysis technology using the diffraction pattern has some advantages. In particular, a specimen is not required for analyzing the substrate and a larger surface of the substrate is analyzed compared with the analysis using the transmission electron microscope. In addition, the above analysis technology using the diffraction pattern facilitates a quantification of analysis results compared with the analysis using the transmission electron microscope.
However, diffraction patterns may not be used for analyzing the crystal characteristics in a circuit pattern of which a size is in a range from a few nanometers to several tens of nanometers. Further, the above analysis technology using the diffraction pattern may not be used for analyzing the crystal characteristics in a composite circuit pattern such as an insulator due to an electric effect caused by the electron beam.
Accordingly, alternate methods and devices are necessary to address these limitations in the prior art.